A lot of tools promise to give your AI memory. Most keep that memory on their servers. Here's an honest look at how Second Brain — self-hosted, open source, free forever — stacks up against the popular alternatives.
Detailed, fair breakdowns — including where each alternative genuinely wins.
A developer memory API and cloud platform. We compare ownership, pricing, graph memory, and who actually stores your data.
Read comparisonA cloud context vault that auto-extracts from your apps. We compare custody, capture style, open source, and cost.
Read comparisonA capable local-first memory engine for coding agents. We compare reach, multi-device sync, tool breadth, and ownership.
Read comparisonThe fundamentals across all four, side by side.
| Second Brain | Mem0 | Unabyss | Agent-Memory | |
|---|---|---|---|---|
| Category | Personal memory you own | Memory API for devs | Cloud context vault | Local memory for coding agents |
| Where it runs | Your Cloudflare account | Self-host or cloud | Vendor cloud | One local machine |
| Open source | MIT | Apache 2.0 | No | MIT |
| You own the data | Always | Self-host only | Hosted for you | Local |
| Free at personal scale | Yes | Free tier / paid cloud | $50 credits, then PAYG | Yes |
| MCP-native | + OAuth | Yes | Yes | Yes |
| Multi-device | Yes | Yes | Yes | No |
| Ready-made apps | CLI · Obsidian · browser · iOS | SDKs · browser · CLI | Web app · MCP | CLI · agent skills |
| Best for | Owning one private brain across every tool | Shipping memory inside your product | Hands-off, auto-built cloud context | One dev's coding agents, offline |
Competitor details reflect each product's public site, repo and listings as of mid-2026 and may change — follow the links in each comparison to verify. Any retrieval-accuracy or token-savings benchmarks cited by these tools are vendor-reported, not independently verified here.
Each alternative is good at something — Mem0 at developer flexibility, Unabyss at hands-off cloud convenience, Agent-Memory at pure-local simplicity. But they ask you to make a trade: keep your memory on a vendor's servers, pay a meter as it grows, or scope it to a single machine.
Second Brain's whole premise is that you shouldn't have to choose. Self-hosted, so you own it. Synced, so it's everywhere. Open source, so you can trust it. Free, so it stays yours.
Lives only in your Cloudflare account — no platform in the middle.
Same brain in Claude, ChatGPT, Cursor, the terminal and your phone.
Dedup, contradiction detection, smart-merge and time-decay built in.
MIT licensed, runs on Cloudflare's free tier at personal scale.
Two minutes to deploy on your own Cloudflare account. Free forever at personal scale. MIT licensed.
